1. Field of the Invention
The present invention relates to an axial gap type generator that is mounted on an engine, and more particularly, to an axial gap type generator in which transfer of heat from the engine to a generator case is suppressed.
2. Description of the Related Art
For general-purpose engines or the like for industrial use, there is known a configuration in which a generator is connected with one end of a crankshaft protruding out of an engine main body.
For instance, a technique disclosed in Japanese Unexamined Patent Application Publication (JP-A) No. H10-4650 provides magnets for power generation at a flywheel that is fixed to the crankshaft end of a motorcycle engine, and coils for power generation, the coils being fixed to the engine, at sites that oppose the magnets in the radial direction.
Furthermore, in recent years, the use of an axial gap type generator has been proposed for compact generator configurations. In the axial gap type generator, stator cores that are fixed to the engine and are provided with power generation coils, and rotor yokes that are provided with magnets for power generation and rotate together with a crankshaft are disposed opposing one another in the center axis direction of the crankshaft.
For instance, in an axial gap type generator disclosed in JP-A No. 2009-216014, a stator core fixed to an engine is disposed in spacing between a pair of rotor yokes that protrude from a crankshaft towards the outer diameter side and are spaced apart from each other in the axial direction.
Also, in an axial gap type generator disclosed JP-A No. 2010-038006, protrusions that are integrally formed with a stator are directly connected with a support member on the side of an engine, thereby enhancing the positioning precision of a stator core with respect to the engine.
When internal temperature rises, the power generation efficiency of axial gap type generators such as those described above drops on account of impaired performance of magnetic bodies, and it is therefore necessary to suppress transfer of heat, generated in the engine, towards the generator.